Well, you'll either need to collect the cards from Arena booster packs for the sets they came in, or else directly 'craft' the specific cards you need using MTG Arena Wildcards - effectively tokens you can exchange for the exact Common, Uncommon, Rare, or Mythic Rare card you want, depending on the type of Wildcard
Flavor Text Its transformation ability is perfect
Enchantment Naked Singularity Cumulative upkeep (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) If tapped for mana, Plains produce , Islands produce , Swamps produce , Mountains produce , and Forests produce instead of any other type
So far, most of what I've said can apply to any creature land, but there are a few reasons that we ought to be particularly excited about Lumbering Falls
Wolfs Bite Rating Always First Pickable One of my most included cards in constructed, and its pretty great in limited formats too